Problem: What do the following two equations represent? $-5x+5y = -4$ $-5x+5y = 5$
Explanation: Putting the first equation in $y = mx + b$ form gives: $-5x+5y = -4$ $5y = 5x-4$ $y = 1x - \dfrac{4}{5}$ Putting the second equation in $y = mx + b$ form gives: $-5x+5y = 5$ $5y = 5x+5$ $y = 1x + 1$ The slopes are equal, and the y-intercepts are different, so the lines are parallel.